fix: activate already created shell (wip)

[kenttonino]

Summary

• When the shell is not yet created, it will create the shell then activate right away.
  • However, when the shell is already created, it will not activate the shell right away, it will just print a message Virtual environment already activated.

Changed

• Once the shell is already created, activate it right away.

Test Plan

• Create shell.
• Deactivate the shell.
• Create/activate the same shell.
  • It should activate the shell right away, instead of just printing the message.

[kenttonino]

Unnecessary. My mistake is I use deactivate. It works with exit.